What change best improves oxygen transmissibility to a patient's cornea?

Improving oxygen transmissibility to the cornea is crucial for maintaining corneal health, especially when fitting contact lenses. The correct answer—by increasing the Dk value—directly enhances the lens's ability to allow oxygen to pass through it. Dk, or water permeability, quantifies how easily oxygen can permeate the contact lens material. Higher Dk values mean that more oxygen is delivered to the cornea, which is essential for cellular metabolism and overall corneal health.

Oxygen is vital for the cornea since it does not have its own blood supply. Adequate oxygen supply reduces the risk of complications such as hypoxia, corneal swelling, and inflammation. Therefore, selecting contact lenses with a higher Dk rating, often seen in newer silicone hydrogel materials, represents a key strategy in contact lens design and fitting for improving corneal oxygenation.

While options like increasing tear exchange or adjusting other parameters can have beneficial effects, they do not directly correlate with enhancing the intrinsic oxygen movement through the lens material itself as the Dk value does.